JPH11349421A - Antimicrobial material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a more inexpensive and simply usable antimicrobial material having high safety and high germicidal effects. SOLUTION: This antimicrobial material is obtained by supporting silver on zeolitic particles so as to provide an amount of the supported silver within the range of 3-30 wt.% based on the zeolitic particles having an average particle diameter within the range of 0.2-30 mm. In the process, the zeolitic particles are preferably a naturally occurring fluorite-based tuff.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zeolite-based antibacterial material utilizing the antibacterial property of silver, and more particularly to a bactericidal material suitable for sterilizing water and an aqueous medium.

[0002]

2. Description of the Related Art In the past, inorganic antibacterial agents have been widely used as antibacterial deodorants and processed fiber products, and subsequently as substitutes for organic antibacterial agents which are easily lost during molding in the field of plastics. Antibacterial components include silver or zinc ions, metallic silver, silver complex salts, silver oxide and the like. These stabilize antimicrobial components and impart sustained release by supporting them on zeolites, ceramics, silica gel, carbon fibers, clay minerals and the like. Among them, silver zeolite made of zeolite having excellent ion exchange capacity and adsorption capacity and silver having strong antibacterial properties (including silver in an ionic state) is a typical inorganic antibacterial agent. .

[0003] Silver zeolite is a much stronger antibacterial agent against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida, Bacillus cereus, black mold, Aureobasidium, etc. than copper zeolite, zinc zeolite and silver zinc zeolite. It is known to exhibit power ("Bactericidal control" 1994)
Year).

In addition, it has been confirmed that silver zeolite has a broad antibacterial spectrum and does not acquire resistance to MRSA (methicylene-resistant Staphylococcus aureus), which has resistance to most antibiotics (see “Chemical Daily” 1993). April issue).

[0005] Silver zeolite has been used as an antibacterial material in fibers, plastics, films, paints and the like, as well as in building materials, toilet bowls, wood and the like, and some of them have already been commercialized.

Various patent applications have been filed and disclosed for antibacterial materials in which silver ions are supported on natural or synthetic zeolites (JP-A-60-1).
No. 00504, JP-A-60-181002,
JP-A-63-260810, JP-A-63-265
809, JP-A-2-111709).

The silver zeolites disclosed in these publications are obtained by incorporating silver ions within the ion exchange capacity of each zeolite into natural or synthetic zeolites by utilizing its ion exchange action, or The amount of silver which has been calcined and is carried on the zeolite is at most about 2.5% by weight. In particular, it is known that the amount of silver supported on naturally produced zeolite-based particles is 0.5 to 1.2% by weight for particles having a particle size of 200 mesh or 2 microns. Since the performance of the silver-supported antibacterial material depends on the amount of silver supported, zeolites supporting such a small amount of silver have a limited effect, especially when used in applications such as water treatment. .

Further, other carriers such as activated carbon, water-soluble glass, silica gel, alumina, and montmorillonite can also carry silver, but have a problem in that the retention capacity is insufficient and desorption is too fast.

An artificial zeolite particle or an A-type zeolite particle obtained by alkali treatment of coal ash, which has been developed as a method for solving this problem, can be used as an inexpensive antibacterial material that can adsorb silver at a high concentration and has a high bactericidal effect. It is provided (JP-A-8-127508). However, since silver zeolite is usually fine particles having a size in the range of 1 to 2 μm, solid-liquid separation is difficult by ordinary precipitation and filtration, and it is hard to say that it is suitable for the purpose of water treatment.

As a method of using a silver zeolite having a large particle size as a water treatment agent, a method of adding a silver zeolite to a synthetic resin to obtain an antibacterial synthetic resin (Japanese Patent Laid-Open No. 4-294782).
JP-A-5-176976), a method for obtaining a silver zeolite compact from silver zeolite (Japanese Patent Publication No. 63-28402), a method for attaching fine silver zeolite powder to the surface of synthetic resin particles, and the like (Japanese Patent Application Laid-Open No. Hei 5-176976). There is. To prepare a silver-supported zeolite compact from silver zeolite, silver zeolite powder is mixed in the same weight ratio as calcium carbonate,
% By weight of bentonite as a binder, and
A method of firing at 0 ° C. for 3 hours is known. However, these methods can improve the particle size of silver zeolite, but still have problems in that a large amount of silver zeolite is required for water treatment, the antibacterial life is not long, and the production cost is low.

[0011]

An object of the present invention is to provide a cheaper silver-supported zeolite which is highly safe, has a high bactericidal effect, and is particularly suitable for easy-to-use water treatment.

[0012]

According to the present invention, zeolite-based particles having an average particle diameter in the range of 0.2 to 30 mm carry silver, and the amount of silver carried is based on the zeolite-based particles. Antimicrobial material in the range of 3 to 30% by weight.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The zeolite-based particles used in the present invention are preferably naturally occurring fluorite-based tuff or a synthetic zeolite formed from a synthetic zeolite and a binder.

The average particle diameter of the particles of the fluorite tuff (mordenite) used in the present invention is more preferably in the range of 0.5 to 5 mm.

The mordenite rock preferably used in the present invention contains, as impurities other than mordenite, quartz, feldspar, α-cristobalite, montmorillonite, mica and the like.
Since magnesium oxide, potassium oxide, and sodium oxide are present, it is desirable to perform a surface activation treatment with caustic soda, sodium chloride, potassium hydroxide, ammonium chloride, or a mixture thereof. In particular, sodium chloride is preferably used as the surface activation treatment agent. The condition of the activation treatment is 100 ° C. for 1 hour, or 5 hours.
The treatment is preferably performed at 5 ° C. for 2 hours, but treatment at room temperature is also possible.

The natural fluorite-based tuff that can be preferably used in the present invention is a mordenite rock from Fukushima. The mordenite rock is not limited to Fukushima but can be used widely in various places.

In producing the antibacterial material of the present invention, the mordenite rock is pulverized to an average of 0.2 to 30.
mm, preferably 0.5 to 5 mm, more preferably 0.6 to 2 mm. The pulverized mordenite rock is desirably washed with water, dried, degassed, and the like, and further activated by an activator solution.

The activator of this mordenite rock pulverized material enhances the silver-supporting ability of the zeolite-based particles of the pulverized material with respect to the pores present on the particle surface and inside the particle. It is preferable to perform the heating treatment in, for example, an about 1 M aqueous sodium chloride solution for 2 hours.

The antibacterial material of the present invention uses, for example, mordenite particles having an average particle size of 0.2 to 30 mm, particularly 0.5 to 5 mm, and a silver concentration of 1000 to 250.
By performing the contact treatment with a silver salt aqueous solution in the range of 0 mg / L, 30 to 30 per gram of the mordenite particles is obtained.
It can be obtained by loading 0 mg, preferably in the range of 50 to 250 mg of silver.

Further, by using silver-supported mordenite particles in combination with silver-free mordenite particles, it is possible to adjust the concentration of silver eluted in the treated water during the water treatment.

On the other hand, silver can be supported on a synthetic zeolite compact such as a synthetic A-type zeolite compact to prepare a silver-supported zeolite compact.

The molded product of the synthetic type A zeolite is, for example,
By performing the contact treatment using an aqueous silver salt solution having a silver concentration of 1,000 to 5,000 mg / L, 1 g of a molded product is obtained.
30 to 300 mg per serving, preferably 50 to 25
A range of 0 mg silver can be supported.

The concentration of silver eluted during the water treatment can be adjusted by using a synthetic zeolite compact carrying a predetermined amount of silver in combination with a silver-free material. As the silver-free material, a silver-free synthetic A-type zeolite compact or silver-free mordenite rock can be used.

The antibacterial material of the present invention can be used for various applications. For example, it can be effectively used in the applications described below. (1) Sterilization of building air-conditioning system, cooling water, etc. (2) Sterilization of drinking water (3) Sterilization of water supply and drainage in cattle, swine, poultry, etc. (4) Sterilization of pool water (5) Circulating warm bath equipment Sterilization and purification of water (6) Prevention of slime generation in kitchen wastewater (7) Sterilization of wastewater from flush toilets (8) Prevention of decay of water-soluble oil used for cooling and lubrication in cutting, grinding, rolling, wire drawing processes, etc. ( 9) Sterilization and purification of rainwater use system (10) Purification of drinking water in remote areas and remote islands (11) Algae prevention of golf course drainage (12) Algae prevention of appreciation ponds and fountains (13) Disinfection of fish tanks ( 14) Prevention of microbial propagation of water purifiers and vibrating ultrasonic humidifiers (15) Purification of effluent from domestic wastewater treatment plants (16) Disease control of cultures in hydroponics

[0025]

[Example 1] The mineral composition was mordenite: 6
8.1%, clinoptilolite: 0%, α-cristobalite: 0.5%, α-quartz: 5.7%, feldspar:
A mordenite rock from Fukushima consisting of 3.3%, montmorillonite: 3.9% and unaltered glass: 13.6% was used as a sample. Its exchangeable cation composition is calcium:
47.1 meq / 100 g, magnesium: 5.5 me
q / 100 g, sodium: 46.8 meq / 100
g, potassium: 46.2 meq / 100 g, and the cation exchange capacity was 174 meq / 100 g. The mordenite particles pulverized and adjusted to particles having an average particle diameter in the range of 1.68 to 30.0 mm are washed with water,
And dried by heating. This was put in a 200 mL Erlenmeyer flask, and 100 mL of deionized water was added to degas. To this was added 10 g of sodium chloride, and the mixture was shaken at 55 ° C. for 2 hours.
After completion of the shaking, the resultant was washed with water, and it was confirmed by an aqueous silver nitrate solution that no chlorine ions remained. Deionized water was added to a predetermined amount of the 1 g / mL silver nitrate aqueous solution to prepare a 200 mL silver nitrate aqueous solution in which the mordenite sample of each weight was dispersed, and the dispersion was shaken at 25 ° C. for 1 hour. Then, the silver concentration (residual silver concentration) in the silver nitrate solution after shaking and the amount of silver supported on the mordenite sample were measured by atomic absorption spectrometry.

Table 1 shows the results.

[0027]

[Table 1] Table 1 銀 Silver nitrate aqueous solution mordenite particles ─── ───────────────────────── Mordenite rock Initial silver amount Residual silver concentration Silver carrying amount (g) (mg / L) (mg / L) ( (Mg of silver / g of mordenite rock) １ 1 1000 640 72 1 1500 1140 72 1 2500 2135 73 2.5 2500 825 134 ────────────────────────────────────

Example 2 According to Example 1, a silver-supported mordenite sample having mordenite particles having an average particle size in the range of 1.68 to 2.00 mm (supporting 56 mg of silver per gram of mordenite) was prepared. Using 20 g of this, column elution was carried out. The sample was packed in a column having an inner diameter of 1.55 cm, and ion-exchanged water was passed through SV5. A sample was taken from the aqueous solution that passed through the column at predetermined intervals, and the concentration of silver eluted during a water flowing time of 35 hours and 20 minutes was measured by an atomic absorption method.
It was in the range of 9 to 5.3 mg / L.

[Example 3]
Column elution was performed using a silver-supported mordenite sample having mordenite particles of the same diameter as in Example 2 (supporting 145 mg of silver per gram of mordenite). Using a column of the same size as in Example 2, silver-free mordenite particles were packed at the bottom of the column at 18 cm, silver-supported mordenite sample at 2 cm at the top of the column, and ion-exchanged water was SV5.
Water was passed. As a result of collecting a sample from the aqueous solution passing through the column at predetermined time intervals, the concentration of silver eluted up to 29 hours and 20 minutes during the water passage time was 0.05 to 0.3 mg / silver.
L range.

Example 4 The same silver-supported mordenite sample as in Example 3 was placed on a column having the same size as in Example 2 by mordenite particles having a size of 2 cm and a particle size of 0.84 to 1.68 mm (without silver). ) Was packed 36 cm below the column, and ion-exchanged water was passed through SV5. As a result, the elution concentration of silver up to 16 hours and 30 minutes in water passage time was 0.0
It was in the range of 1 to 0.06 mg / L.

FIG. 1 shows the results of Examples 2 to 4. In FIG. 1, -−- indicates the silver concentration (mg / L) in the eluted aqueous solution with respect to the elution time when the monolayer of the silver-supported mordenite particles packed in the column was eluted in Example 2. -Indicates the results in Example 3 when the silver-supported mordenite particles were the upper layer, and the unsupported mordenite particles were the lower layer, and-□-in Example 4
The result when the filling amount of the unsupported mordenite particles in the lower layer is increased with respect to the filling amount of the silver-supported mordenite particles in the upper layer, as compared with the case of Example 3.

According to Examples 2 to 4, the elution concentration of silver was in the range of 2.9 to 5.3 mg / L in Example 2, whereas in Example 3, the elution concentration of silver was in the range of 0.05 to 0.5 mg / L. 3mg / L
It was confirmed that the silver elution concentration could be controlled to be even lower than in Example 3 in Example 4.

Example 5 Using the method of supporting silver on natural zeolite in Example 1, silver was carried on a synthetic A-type zeolite compact. First, the synthetic A-type zeolite molded body is composed of 70% synthetic A-type zeolite and Kibushi clay:
It was obtained by mixing with a 2% carboxymethylcellulose (CMC) solution at a ratio of 25% and bentonite: 5%, followed by heating and baking at about 600 ° C. Next, silver was supported on the zeolite compact by the following method. After washing the particles of the zeolite molded body having a particle size in the range of 1.68 to 2.00 mm and drying by heating at 100 ° C.,
Place in a 200 mL Erlenmeyer flask and add 100 parts of ion-exchanged water.
mL was added and degassed. Deionized water is added to a predetermined amount of a 1 g / mL silver nitrate aqueous solution to prepare a 200 mL silver nitrate aqueous solution in which a zeolite molded article sample of each weight is dispersed, and the dispersion is shaken at 25 ° C. for 1 hour. did. And the concentration of silver in the silver nitrate solution after shaking (residual silver concentration)
And the amount of silver carried on the zeolite sample was measured by atomic absorption spectrometry. Then, the silver concentration (residual silver concentration) in the silver nitrate solution and the solution after shaking, and the amount of silver carried on the synthetic zeolite compact were measured by atomic absorption spectrometry.

Table 2 shows the results.

[0035]

[Table 2] Table 2 銀 Aqueous silver nitrate aqueous zeolite particles ─ ──────────── ────────────── Synthetic zeolite Initial silver amount Residual silver concentration Silver carried amount Molded body (g) (mg / L) (mg / L) (silver mg / zeolaoite molded article g) ０ 0. 2 2000 1805 97.5 0.2 4000 3560 220 0.2 5000 4620 190 0.5 2500 2500 2260 96 2 1000 600 40 2 2000 1165 83.5 2 2500 1650 85 4 1500 600 45 ────────────────────────────

[0036]

The antibacterial material of the present invention is a silver zeolite in which silver is supported on zeolite having a large particle size at a high concentration, the silver equilibrium concentration is not high, and the antibacterial life is long.
Further, from the viewpoint of safety, the amount of silver eluted can be adjusted, and by using natural fluorite tuff and synthetic zeolite as zeolite, it can be effectively used as an inexpensive water treatment material.

[Brief description of the drawings]

FIG. 1 is a view showing the results of a silver ion elution test of a silver-supported mordenite sample according to the present invention.

 ──────────────────────────────────────────────────続 き Continuation of front page (71) Applicant 599029143 Kimiko Sukekawa 1-3-6 Sotokanda, Chiyoda-ku, Tokyo (72) Inventor Taro Ozawa 1-9-17-1 Chuo, Ota-ku, Tokyo

Claims (5)

[Claims] 1. Zeolite particles having an average particle size in the range of 0.2 to 30 mm are loaded with silver, and the amount of silver carried is in the range of 3 to 30% by weight based on the zeolite particles. An antibacterial material characterized by being made to be. 2. The antibacterial material according to claim 1, wherein the zeolite-based particles are fluorite-based tuff produced naturally. 3. The antibacterial material according to claim 2, wherein the average particle size of the particles is in the range of 0.5 to 5 mm. 4. The antibacterial material according to claim 2, wherein an activation treatment is performed on pores present on the particle surface and inside the zeolite-based particles. 5. The antibacterial material according to claim 1, wherein the zeolite-based particles are formed from a synthetic zeolite and a binder.